The American College of Cardiology (ACC) has recently developed Appropriateness Criteria (AC) for coronary revascularization to support the rational and judicious use of percutaneous coronary intervention (PCI). Because a modified Delphi approach was used, there is an absence of clinical evidence to support the appropriateness ratings for most of the AC scenarios. This proposal will test the feasibility of applying the AC in routine clinical practice, assess variations in rates of appropriate and inappropriate PCI use nationally, and examine whether the AC are associated with objective measures of patient-centered benefit. These aims are aligned with the NIH's priorities of improving the efficiency and appropriateness of care. Specific Aim 1 will examine the feasibility of applying the AC in clinical practice. Data templates that capture the requisite patients' clinical, medication, imaging, and angiographic data for the AC will be developed and prospectively implemented in a 4-center study. In addition, the National Cardiovascular Data Registry (NCDR) Cath/PCI data collection tool will be modified to capture the necessary AC data elements. Finally, linking algorithms to map individual PCI procedures to the AC will be developed. Specific Aim 2 will describe the prevalence of and variations in PCI appropriateness across hospitals participating in the NCDR Cath/PCI registry. This analysis will provide national prevalence estimates of PCI procedures that are rated appropriate, inappropriate, or uncertain, per the AC; examine the variability in the proportion of appropriate and inappropriate PCIs across institutions; and determine the degree to which overuse may account for wide variations in PCI use by correlating rates of inappropriate and uncertain PCIs within Medicare Hospital Referral Regions with variability in overall PCI use from the Dartmouth Atlas. Specific Aim 3 will validate the ratings of the AC with objective measurements of patient benefit. Through a 4-center prospective study, 6-month changes in angina symptoms and quality of life will be assessed with the Seattle Angina Questionnaire (SAQ) and the EQ-5D instruments. Measurements of change in symptom burden and quality of life will then be correlated with ratings of appropriateness to determine if the AC are associated with objective measures of clinical benefit. Specific Aim 4 will involve derivation of a shortened SAQ to facilitate its use in routine practice. As patients' symptoms are a critical determinant of the AC ratings, and as assignment of patients' symptom status by physicians can be highly variable, direct assessment of symptoms from patients' responses to the SAQ offers the opportunity for substantially greater reliability and fidelity. However, the full SAQ is too cumbersome to routinely collect in clinical practice. Using the extensive repository of SAQ data at our institution, a parsimonious SAQ will be derived and validated to facilitate its use in routine practice.